The prevents food or liquids from getting into the lungs.

the Epiglottis prevents food or liquids from entering the lungs.

Explanation:

when you swallow it covers the enterance to the lungs. Hope this helps :)

Epiglottis

Explanation:

During breathing, air travels from your mouth and pharynx into the larynx (toward your lungs). When you swallow, a flap called the epiglottis moves to block the entrance of food particles into your larynx and lungs. That prevents food from entering your lungs.

when you rub, you also apply pressure, that pressure can urge the poop to come out. i think that when your rubbing, you also might be slightly breaking it up and that can further fill the stomach.